1. Field
The present disclosure relates to a light-emitting device and a method of manufacturing the same.
2. Description of the Related Art
A light-emitting device such as a light-emitting diode (LED) is used as a semiconductor light source with a pn junction of compound semiconductors and emits different light colors.
For example, a nitride-based LED made of group III-V compounds such as gallium nitride (GaN), indium nitride (InN), and aluminum nitride (AlN) may be widely used as a light-emitting device that emits short-wavelength light (ultraviolet light and green light), and in particular, blue light. Light-emitting devices provide a long lifespan, a compact and lightweight design, and low-voltage driving due to the high directivity of light emitted thereby. Furthermore, light-emitting devices are highly resistant to shock and vibration and do not require preheating or complex driving. They may also be packaged into different shapes and sizes and may be widely used in various applications.
As an approach to fabrication of a light-emitting device such as an LED, a vertical structure has been proposed. This approach includes stacking compound semiconductor layers on an insulating substrate such as a sapphire substrate that is known to best satisfy lattice matching conditions for crystal growth and removing the insulating substrate. Such vertical light-emitting devices are classified into light-emitting devices in which p- and n-electrodes are disposed on the same surface of a compound semiconductor structure and light-emitting devices in which n- and p-electrodes are disposed on the opposite surfaces thereof. A light-emitting device in which the n- and p-electrodes are disposed on the same surface of a compound semiconductor structure may provide better current spreading performance while reducing the drawback of blocking the propagation of light due to the presence of the electrodes.
Conventionally, when electrodes are formed on a compound semiconductor layer and a substrate, an electrode material is covered with an insulating material in order to have electrical insulation between the electrodes having opposite polarities. Furthermore, the manufacturing process of a wafer-level chip size package includes forming an insulating material and depositing a conductive material on the insulating material in order to provide an electrical conduction between a substrate and a compound semiconductor layer. This may cause misalignment, resulting in a high failure rate. This approach may also require a space adjacent to a compound semiconductor layer for forming an insulating layer and depositing a conductive material thereon, thereby decreasing a light-emitting area compared to the area of the compound semiconductor layer.